1. Field of the Invention
The present invention relates generally to a system for securing and protecting cargo. The system is particularly suited for use with palletized cargo for aircraft.
2. Description of the Related Art
A significant portion of cargo hauled by modern commercial aircraft must be arranged on a pallet and loaded into a cargo section within the aircraft. The palletized cargo is usually secured to the pallet using a number of nylon or rope straps which are affixed at their ends to portions of the pallet. If it is desired to protect the cargo from weather or other external elements, the cargo is typically shrink-wrapped in a plastic covering before the straps are emplaced around it.
The present strapping system is often unreliable and can lead to loss of or damage to the cargo. How well the cargo is secured to the pallets will depend greatly upon the experience and the strapping techniques used by the personnel employed to secure the cargo. A shortage of straps over portions of the cargo may allow these portions to shift during flight resulting in damage to the shrink wrap and/or the cargo within. The use of shrink-wrapping is also wasteful as the plastic material used to cover the cargo may only be used one time. Use of this method also requires significant time and manpower. An average of 30-45 minutes is needed to shrink-wrap and lash a cargo pallet using this system.
Alternative systems for securing cargo to pallets have been developed. Although these alternatives provide for weatherproofing and greater security against cargo being dislodged, they are ill equipped to deal with irregularly shaped cargo loads and are prone to systemic failure.
An arrangement is known, for instance, which employs a cargo lashing net made up of a plurality of elongated stringers arranged in net form and secured to each other at overlapping points by appropriate sewn thread. The net may be secured to the pallet by the attachment of hooks from the net to connecting plates which are flexibly secured to the pallet. Although it provides for more secure lashing, this design does not weatherproof or protect the cargo against external elements. Adjustment of the net to loads of non-uniform heights and widths is also difficult. In addition, if one or two of the elongated stringers is damaged or broken, the entire net may be compromised and require replacement.
Another system for securing cargo uses a blanket of strong canvas duck, nylon, or the like which is integral with cross strips of webbing stitched or otherwise suitably secured to the blanket. The ends of the strips are provided with hooks which are adapted to be secured to hold-down bolts or the like within a pallet. The strips of webbing are provided with takeup buckles to permit the cargo cover to be tightened down over cargo loads. The blanket may include flap extensions to fold down over the sides of the cargo. Slide fasteners or laced fastenings may be used for drawing the flap extensions closely together at the comers. Portions of the blanket may be folded to reduce it to half or quarter size. Unfortunately, this cargo blanket does not provide suitable security for irregularly shaped loads. The take-up straps are inherently limited in adjustability, and a broken or worn section of webbing may compromise the entire securing apparatus.
There is a continuing need for a more versatile and reusable cargo securing system, which is capable of protecting and securing irregularly shaped loads and which may be easily repaired in the event of failure of a securing strap.